//加密、解密算法封装：
function Base64()  
{  
    let _keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=" ;
    this.encode = function(e){  
        var t="";  
        var n,r,i,s,o,u,a;  
        var f=0;  
        e=_utf8_encode(e);  
        while(f<e.length){  
            n=e.charCodeAt(f++);  
            r=e.charCodeAt(f++);  
            i=e.charCodeAt(f++);  
            s=n>>2;  
            o=(n&3)<<4|r>>4;  
            u=(r&15)<<2|i>>6;  
            a=i&63;  
            if(isNaN(r)){  
                u=a=64  
            }else if(isNaN(i)){  
                a=64  
            }  
            t=t+_keyStr.charAt(s)+_keyStr.charAt(o)+_keyStr.charAt(u)+_keyStr.charAt(a)  
        }  
        return t  
    };
    this.decode = function(e){  
        var t="";  
        var n,r,i;  
        var s,o,u,a;  
        var f=0;  
        e=e.replace(/[^A-Za-z0-9+/=]/g,"");  
        while(f<e.length){  
            s=_keyStr.indexOf(e.charAt(f++));  
            o=_keyStr.indexOf(e.charAt(f++));  
            u=_keyStr.indexOf(e.charAt(f++));  
            a=_keyStr.indexOf(e.charAt(f++));  
            n=s<<2|o>>4;  
            r=(o&15)<<4|u>>2;  
            i=(u&3)<<6|a;  
            t=t+String.fromCharCode(n);  
            if(u!=64){  
                t=t+String.fromCharCode(r)  
            }  
            if(a!=64){  
                t=t+String.fromCharCode(i)  
            }  
        }  
        t=_utf8_decode(t);  
        return t  
    };
    let _utf8_encode = function(e){  
        e=e.replace(/rn/g,"n");  
        var t="";  
        for(var n=0;n<e.length;n++){  
            var r=e.charCodeAt(n);  
            if(r<128){  
                t+=String.fromCharCode(r)  
            }else if(r>127&&r<2048){  
                t+=String.fromCharCode(r>>6|192);  
                t+=String.fromCharCode(r&63|128)  
            }else{  
                t+=String.fromCharCode(r>>12|224);  
                t+=String.fromCharCode(r>>6&63|128);  
                t+=String.fromCharCode(r&63|128)  
            }  
        }  
        return t  
    };  
    let _utf8_decode = function(e){  
        var t="";  
        var n=0;  
        var r=0,c1=0,c2=0;  
        while(n<e.length){  
            r=e.charCodeAt(n);  
            if(r<128){  
                t+=String.fromCharCode(r);  
                n++  
            }else if(r>191&&r<224){  
                c2=e.charCodeAt(n+1);  
                t+=String.fromCharCode((r&31)<<6|c2&63);  
                n+=2  
            }else{  
                c2=e.charCodeAt(n+1);  
                c3=e.charCodeAt(n+2);  
                t+=String.fromCharCode((r&15)<<12|(c2&63)<<6|c3&63);  
                n+=3  
            }  
        }  
        return t  
    }  
};  
 
export {
    Base64
}